OUTER MORAINE OF THE MIAMI LOBE. 315 



A well boriug in Buck Creek Valley west of Market street, Spring- 

 field, penetrated about 100 feet of cobble and gravel before striking rock. 

 This seeins remarkable, since the valley here is not more than 100 yards 

 in width, and has rock bluffs on either side, the height of the bluffs being 

 about 130 feet above the rock floor. A plain, on which tliere is some 

 cobble and coarse gravel and an occasional large bowlder, borders this 

 rock-bound channel on the south. South of this plain, at an altitude per- 

 haps 20 feet higher and near the railroad stations and post-office, there was 

 originall}^ much boggy land with peat underlain by sand. South of the 

 railroad stations, on a terrace-like plain 25 to 30 feet higher, there is gravel, 

 but a line of springs issuing near the base of this bench indicates an imper- 

 vious substratum, probably clay, at that level. South from the plain just 

 described is an undulating tract unmodified by fluvial action. The l:)euch 

 last mentioned apparently represents the highest terrace and stands about 

 75 feet above Buck Creek. North of Buck Creek the uplands in the city 

 of Springfield rise to a height of 75 to 100 feet, and, as stated above, con- 

 tain till as well as assorted material. The lower plain which borders the 

 immediate bluffs of Buck Creek was apparently occupied by a stream 

 leading westward after the Miami lobe had withdrawn. The relationsliip 

 of the upper plain to the glacial deposits is not determined. 



The abandoned or concealed valley 3 miles west of Springfield, to 

 which Orton has called attention,^ lies Avest of Mad River Valley in a nearly 

 plane tract. The <)ld valley led directly across the neck of land around 

 which the river now flows. It was so completely filled with drift tliat 

 no suspicion of its existence was aroused during a railway survey across 

 it, and it was discovered in the attempt made by the railway company to 

 tunnel it. It was then found that the drift along this line extends at least 

 to the level of Mad River. The deep cutting made by the railway exposes 

 an interesting but complex section, there being two alternations of yellow 

 and blue tills. At the top is a yellow till 10 to 12 feet thick which follows 

 the arching surface of the ridge, beneath which is a bed of blue till 2 

 to 10 feet thick, its thickness being greatest under the crest of the ridge. 

 Under this is a bed of 3^ellow till about 6 feet in thickness, which extends 

 both east and west beyond the limits of the blue till, and there immediately 

 underlies the upper bed of yellow till. Beneath this bed is the main deposit 



' Geoloyy of Ohio, Vol. I, pp. 460-461. 



